1. Field of the Invention
This invention is related to a multi-functional motor fuel additive composition which is active in preventing deposits from forming in port fuel injectors and on intake valves. More particularly, this invention relates to:
I) a multi-functional motor fuel additive composition comprising (a) a mono-polyalkenylsuccinimide, (b) a bis-polyalkenylsuccinimide and (c) a heavy oil; PA1 II) a motor fuel composition comprising a major portion of a base fuel and a minor portion of the multi-functional motor fuel additive of the present invention; and PA1 III) a concentrate of the multi-functional motor fuel additive of the present invention. PA1 between about 65 wt. % and about 95 wt. %, based upon the total weight of the first component, of a bis-succinimide of general formula: ##STR1## and between about 35 wt. % and about 5 wt. %, based upon the total weight of the first component, of a mono-succinimide of general formula: ##STR2## where R and R' are polyalkenyl radicals with average molecular weights of about 300 to about 4000 and n and m are integers between about 1 and about 6; and
2. Description of Related Information
Combustion of a hydrocarbon motor fuel in an internal combustion engine generally results in the formation and accumulation of deposits on various parts of the combustion chamber as well as in the fuel intake and on the exhaust systems of the engine.
The accumulation of deposits in the port fuel injectors of the engine, in particular, tend to cause misfueling, which promotes incomplete fuel combustion and leads to rough engine idling and engine stalling. Excessive hydrocarbon and carbon monoxide exhaust emissions are also produced under these conditions. It would therefore be desirable from the standpoint of engine operability and overall air quality to provide a motor fuel composition which minimizes or overcomes the above described problems.
Another problem common to internal combustion engines is the formation of intake valve deposits. Intake valve deposits interfere with valve closing and eventually result in poor fuel economy. Such deposits interfere with valve motion and valve sealing, cause valve sticking, and, in addition, reduce volumetric efficiency of the engine and limit maximum power. Valve deposits are usually a result of thermally and oxidatively unstable fuel or lubricating oil oxidation products. Hard carbonaceous deposits collect in the tubes and runners that conduct the exhaust gas recirculation (EGR) gases. These deposits are believed to be formed from exhaust particles which are subjected to rapid cooling while mixing with the air-fuel mixture. Reduced EGR flow can result in engine knock and NO.sub.x emission increases. It would therefore be desirable to provide a motor fuel composition which minimizes or overcomes the formation of intake valve deposits and subsequent valve sticking problems.
Thus, today's gasoline technology requires additives which are multi-functional. This presents an additional problem. Multi-functional additives are difficult to develop, because improved activity in one area of gasoline engine deposit control can result in reduced deposit control in another area. An example of this problem occurs with the aforementioned port fuel injectors and intake valves. An additive which improves port fuel injector detergency usually results in an increase in intake valve deposits: an undesirable result. It would therefore be desirable to provide a motor fuel composition containing a multi-functional additive which minimizes or overcomes this problem by controlling the formation of deposits in port fuel injectors, without aggravating the intake valve deposit problem.
Therefore, it is an object of the present invention to provide both a multi-functional additive composition and a motor fuel composition which significantly reduce the tendency of port fuel injectors to become plugged with deposits. It is another object of the present invention that the multi-functional additive composition and the motor fuel composition not only reduce port fuel injector deposits, but also do not aggravate the tendency of intake valves to form deposits. Yet another object of the present invention is to provide a concentrate composition comprising the above described multi-functional motor fuel additive for use in a motor fuel composition.
It is a feature of this invention that port fuel injectors in engines which are operated on the motor fuel composition of the present invention develop a significantly smaller amount of deposits than port fuel injectors in engines which are operated on motor fuels which do not contain the multi-functional additive composition of the present invention. It is another feature of this invention that the decrease in port fuel injector plugging is obtained without a concomitant increase in the formation of intake valve deposits.
Motor fuel compositions of the instant invention are advantageous in that they significantly reduce the accumulation of deposits in port fuel injectors, with a concomitant reduction of harmful emissions and increase in engine operability. Simultaneously, intake valve deposit formation is reduced, with a concomitant reduction in valve sticking and increase in valve life, cold starting ability and overall engine operability.